While each BI vendor can demonstrate a laundry list of things they do, and marketing terms they use, to distinguish from the other, there is a lot of parity between these two leading BI products. I could distinguish them further, but although you provided a good list, I'd need to know more. Looking at this list quickly, I think you'd find either product can fulfill most of these requirements, except for HeatMaps – I'm not sure about that.
These decisions these days come down to broader issues as well as the technical ones. These issues include whether you'll go with best-of-breed vs. a single vendor, your already installed components, the local team you deal with and the deal itself.
One caution about Cognos is their architectures tend to be more "data mart" than "data warehouse" and their cube structures can tend to multiply and divide if you are not careful. The simplest approach, and one which I'd need to see evidence to stray from, is the relational approach.
And remember, it's going to be just as much about execution as it is selection. Don't allow hangovers about the selection cast a pall on executing the business strategy with the chosen tool.
This was first published in February 2009